Nonvalvular atrial fibrillation (AF) is a potent predictor of first and recurrent stroke, affecting more than 2.7. million Americans. An estimated 14-38% of patients with ischemic stroke have AF. The frequency of ischemic stroke events in patients with AF is directly proportional to the mean age of populations studied. Of note, this data may be an underestimation due to the difficulty of detecting asymptomatic or paroxysmal AF. The presence of AF greatly increases the risk of ischemic stroke, and this effect is seen more prominently as age increases and in female populations. The prevalence of ischemic stroke associated with AF is less than 10% in patients under the age of 50, but rises to over 50% in patients above 90. years of age. In general, ischemic stroke patients with AF tend to be older, female, and have more comorbidities than patients with ischemic stroke without AF.
Groshans, K. A., & Leary, M. C. (2017). Management of Atrial Fibrillation. In Primer on Cerebrovascular Diseases: Second Edition (pp. 759–766). Elsevier Inc. https://doi.org/10.1016/B978-0-12-803058-5.00146-6